SC - The Structure and Function of the Genome

Question 1

What are Chromosomes Territories (CTs)?

Answer 1

Domains occupied by chromosomes within the nucleus

Question 2

How would you describe the distribution of chromosomes?

Answer 2

Non-random

Question 3

What is CT position correlated with?

Answer 3

Gene content

Question 4

Where in the nucleus would more active chromosomes lie?

Answer 4

Interior

Question 5

What do interphase chromosomes contain?

Answer 5

Regions of:
- CLOSED chromatin- Heterochromatin
- OPEN chromatin- Euchromatin

Question 6

Describe the features of Heterochromatin?

Answer 6

COMPACT and NOT TRANSCRIBED

Question 7

Describe the features of Euchromatin?

Answer 7

RELAXED and TRANSCRIBED

Question 8

What CT is known to hold/separate ‘open’ and ‘closed’ chromatin?

Answer 8

Topologically-Associated Domains (TADs)

Question 9

What determines the eu- or hetero- chromatin state?

Answer 9

Histone Modifications
(Amount of methyltion vs acetlylation determines open vs closed)

Question 10

What are 2 Histone-modifying enzymes?

Answer 10

Histone AcetylTransferases (HATs)
- Transfer ‘acetyl’ groups onto histone tails
Histone MethylTransferases (HMTs)
- Transfer ‘methyl’ groups onto histone tails

Question 11

Why are cells different if they have the same DNA?

Answer 11

• Differential chromatin state
• Differential coding gene expression
• Differential non-coding gene expression

Question 12

What are mutations within the non-coding region identified as?

Answer 12

Pathogenic

Question 13

Out of cis-acting and trans-acting non-coding elements, which one is transcribed and made into RNA?

Answer 13

Trans-acting (Regulatory RNAs, Structural RNAs)

Not Cis-acting (Enhancers, Silencers, Telomeres, Centromeres, Insulators)

Question 14

What are the 2 types of non-coding RNA?

Answer 14

Long Non-Coding RNAs (lncRNAs)
- Longer than 200nt
- Contain poly-A tails
Small Non-Coding RNAs (ncRNAs)
- Shorter than 200
- Contain poly-A tails
- Mainly regulatory